Treatment of NZB/NZW mice with Ribavirin, a broad spectrum antiviral drug, has been very effective. Renal deposits of immune complexes can be prevented. Such treatment is potentially applicable to humans with SLE. A diet enriched in a polyunsaturated fatty acid eicosapentaenoic markedly retards the development of autoimmunity in (NZB x NZW) F1 females. This works even after the onset of disease. Thymectomy markedly retards autoimmunity in MRL-lpr/lpr mice. Cyclophosphamide is effective treatment in a variety of autoimmune strains unrelated to the cellular basis of illness or the nature (B or T cell) of the proliferating cells.